The California Environmental Protection Agency, Department of Toxic Substances Control (DTSC) has made a final decision to certify the following company's hazardous waste environmental technology listed below:

Chapter 412, Statutes of 1993, Section 25200.1.5., Health and Safety Code, enacted by Assembly Bill 2060 (Weggeland) and effective January 1, 1994 authorizes DTSC to certify the performance of hazardous waste environmental technologies. Only technologies that are determined not to pose a significant potential hazard to the public health and safety or to the environment when used under specified operating conditions and which can be operated without specialized training and with minimal maintenance may be certified. Incineration technologies are explicitly excluded from the certification program.

The purpose of the certification program is to provide an in-depth, independent review of technologies at the manufacturer's level to facilitate regulatory and end-user acceptance and to promote and foster growth of California's environmental technology industry.

DTSC makes no express or implied warranties as to the performance of the manufacturer's product or equipment. The end-user is solely responsible for complying with the applicable federal, state, and local regulatory requirements. Certification does not limit DTSC's authority to require additional measures for protection of public health and the environment.

By accepting certification, the manufacturer assumes, for the duration of certification, responsibility for maintaining the quality of the manufacturered equipment and materials at a level equal or better than was provided to obtain certification and agrees to be subject to quality monitoring by DTSC as required by the statute under which certification is granted.

DTSC's notice to certify was published in the California Regulatory Notice Register Volume 96. The DTSC's final certification shall be effective from July 15, 1996 to July 15, 1999.

Additional information supporting DTSC's final certification decisions is available from:

Under the authority of Section 25200.1.5 of the California Health and Safety Code, DTSC hereby certifies the D TECH RDX ® manufactured by Strategic Diagnostics, Inc. as a Measurement Technology. The D TECH RDX assay system uses enzyme-linked immunosorbent assay (ELISA) technology. It differs from other systems in that polyclonal antibodies are supplied attached to latex particles. RDX in water is assayed directly; for soils, the system uses extraction with acetone. The immunoassay system is semi-quantitative. Provided that the materials are used properly, detection is possible at 5 to 45 ppb in water and 0.5 to 6.0 ppm in soil; ranges can be extended upward by dilution of the extracts.

Quantitative readings about a selected target level are obtained by comparison with a color chart or in a microprocessor-equipped, hand-held, battery-operated reflectometer. The reaction with other nitroaromatics is insignificant except for HMX (octahydro-1,3,5-trinitro-1,3,5,7-tetranitro- 1,3,5-triazine). TNT, dinitrotoluenes, 2,4-dinitrophenol, and mononitroaromatics do not interfere. Differences in the extraction efficiency of RDX from various soils may cause positive or negative errors in the immunoassay results. Users should evaluate these factors before attempting to quantify results.

Great care is required and established safety measures must be observed in sampling and handling soil containing explosives. As with similar assays, certain temperature controls are required for reagent storage and for carrying out the assay. The assay should be used only by trained individuals to reduce operator-caused variability.

Limitations of Certification

DTSC makes no express or implied warranties as to the performance of the manufacturer's product or equipment. Nor does DTSC warrant that the manufacturer's product or equipment is free from any defects in workmanship or material caused by negligence, misuse, accident, or other causes.

DTSC believes, however, that the manufacturer's product or equipment can achieve performance levels set out in this Certification. Said belief is based on a review of the data submitted by the manufacturer and other information, and is based on the use of the product in accordance with the manufacturer's specifications.

This Certification is subject to the conditions set out in the regulations to-be-developed, such as the duration of the Certification, the continued monitoring and oversight requirements, and the procedures for certification amendments, including decertification.

By accepting this Certification, the manufacturer assumes, for the duration of the Certification, responsibility for maintaining the quality of the manufactured materials and equipment at a level equal or better than was provided to obtain this Certification and agrees to be subject to quality monitoring by DTSC as required by the law under which this Certification is granted.

Basis for Certification

The Documentation submitted by the manufacturer and other studies are listed in the evaluation report on which this certification is based. The manufacturer has asserted that certain materials contain proprietary information and therefore should not be subject to public disclosure.

Recommended Applications

The assay was developed for the semiquantitative determination of RDX. A semiquantitative determination will provide a response, interpreted as either positive or negative, at one or several predetermined detection or target levels. Target levels are usually chosen to have relevance to a specific situation (such a regulatory action or cleanup level).

A comprehensive process of developing data quality objectives (DQO) was published by U.S. EPA under the U.S. Superfund Program. It provides guidance for analytical method QA/QC as applied to field investigations for contaminated soils. The process is intended for site-specific sampling plans. Here the immunoassay would generally qualify as a Level 2 (field analysis) method, subject to confirmation by a Level 3 method (confirmation and quantification, e.g., EPA Method 8330) applied predominantly to positive results. We recommend that minimum quality control should include a method blank and duplicates at 10 to 20 percent, or one per batch or per matrix, whichever is the more frequent, in addition to the samples required for confirmation. The use of proficiency evaluation and spiked samples should depend on project-specific needs.

U.S. EPA SW-846 Method 8330 is available and currently approved for establishing or confirming concentrations of RDX.

"Screening" and "Preliminary Site Investigations"

The immunoassay can assist in preliminary site investigations (Phase I), if there are compelling historical data to indicate the presence of TNT as in explosives manufacturing and handling and ordnance open burn and detonation operations. If used on samples with unknown potential for analytical interferences and matrix effects, confirmatory analysis is needed for every positive immunoassay result. The user should be aware of the reactions given by chemically related nitroaromatics which are common contaminants and breakdown products of TNT. No negative determinations can be made without taking into account the specificity of the assay and its possible susceptibility to interferences and matrix effects. In the absence of other regulations and guidelines, we recommend that assay results be confirmed in the following manner:

For the delineation of TNT contamination in a coherent mass of soil, the required frequency of confirmation by an approved method resulting in identification and quantification is at least 10 percent of the samples testing positive at the target or action level applicable at the site. In the event that fewer than ten samples meet these criteria, at least one positive sample shall be confirmed. Higher rates of confirmation apply if there is a potential for chemical interferences.

Ten to twenty percent of results which are above the detection level but below the target or action level should be confirmed by an approved, fully quantitative method, except that a higher rate of confirmation may be necessary if the results are to be used in health risk assessments;

Five to ten percent of all negative results, but no less than one result from each site or suspect area, should be confirmed.

If appropriate protocols are followed, the immunoassay can be used to advantage to classify contaminated soils as to low, medium, or high contamination and to determine which samples would provide the most information from laboratory analysis.

"Site Investigations" and "Remedial Actions"

Here the testing is expected to proceed under a site-specific Quality Assurance Project Plan (QAPP). Immunoassay and other field measurements will be bracketed in time and space by qualitative and fully quantitative analyses. Generally, a site is first characterized by the use of approved, fully qualitative and quantitative analytical methods as to the nature and level of contamination in key sampling locations and as to the presence of substances that may interfere with the use of the immunoassay. After such initial characterization, the immunoassay can be used in the comprehensive mapping of the site with respect to identified contaminant(s) to which the immunoassay responds. The percentage of samples that would be confirmed by another approved, fully quantitative method would be as stipulated in the QAPP; the project manager could call for additional confirmatory testing if such a need is indicated in the course of the investigation. During site cleanup, the QAPP would provide for use of the immunoassay to monitor progress. Confirmatory laboratory testing would occur before a decision on site closure is made.

Regulatory Implications

DTSC's Certification is based on the technology's performance and by itself does not change the regulatory status of RDX testing; it should, however, facilitate and encourage the acceptance of this technology where a project's data quality objectives can be met by its use. To this end, DTSC's findings should contribute to a consideration of this technology in regulated activities, depending on each program's objectives and constraints. State-regulated disposal facilities may contact state permitting officers for use of the immunoassay for operational monitoring. Other local and state government permitting authorities may take this certification under consideration when making their permitting decisions. Project leaders may use this assay if it meets data quality objectives.